Finding the Third Proportional to 12,390 and 18,586.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,390 : 18,586.50 = 18,586.50 : x
2. Step 2: Convert to fraction form
   12,390/18,586.50 = 18,586.50/x
3. Step 3: Cross multiply
   12,390x = 18,586.50 × 18,586.50
4. Step 4: Simplify right side
   12,390x = 345,457,982.25
5. Step 5: Solve for x
   x = 345,457,982.25/12,390
6. Step 6: Final answer
   x = 27,882.00